Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Journal of Korean Institute of Communications and Information Sciences
Journal Basic Information
Journal DOI :
The Korean Institute of Communications and Information Sciences
Editor in Chief :
Volume & Issues
Volume 24, Issue 12B - Dec 1999
Volume 24, Issue 12A - Dec 1999
Volume 24, Issue 11A - Nov 1999
Volume 24, Issue 10B - Oct 1999
Volume 24, Issue 10A - Oct 1999
Volume 24, Issue 9B - Sep 1999
Volume 24, Issue 9A - Sep 1999
Volume 24, Issue 8B - Aug 1999
Volume 24, Issue 8A - Aug 1999
Volume 24, Issue 7B - Jul 1999
Volume 24, Issue 7A - Jul 1999
Volume 24, Issue 6B - Jun 1999
Volume 24, Issue 6A - Jun 1999
Volume 24, Issue 5B - 00 1999
Volume 24, Issue 5A - 00 1999
Volume 24, Issue 4B - 00 1999
Volume 24, Issue 4A - 00 1999
Volume 24, Issue 3B - 00 1999
Volume 24, Issue 3A - 00 1999
Volume 24, Issue 2B - 00 1999
Volume 24, Issue 2A - 00 1999
Volume 24, Issue 1B - 00 1999
Volume 24, Issue 1A - 00 1999
Volume 24, Issue 12 - 00 1999
Volume 24, Issue 11B - 00 1999
Selecting the target year
An Improved Link Access Scheme Using Carrier Sensing Mechanism In DSRC.
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1453~1461
In this paper, we propose a new scheme that improve the performance of the conventional link access scheme in DSRC MAC and evaluate the performance of the proposed scheme. By using carrier sensing mechanism in random access channels, the proposed scheme can reduce the probability that the collisions among the link access traffics with different priorities may occur in random access channels, and provide differentiated link access delays according to the priorities. Furthermore, the proposed scheme can improve the performance of link access by using modified reservation mode. According to simulation results, it is shown that the proposed scheme is better than conventional method in view of the mean access delay and throughput in random access channels.
Performance of Hybrid DS/FH Spread-Spectrum Systems in Cellular Packet Radio Network
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1462~1470
In this paper, the performance of packet radio networks using the ALOHA protocol in Rayleigh fading channels is analyzed in terms of the capture probability and the throughput. We consider capture effect in order to increase the probability of the channel access and to include cellular environment we assume that the traffic is a truncated bell-shaped distribution. The packet proposed in this paper consists of a competition part and a data part to decrease the probability of collision in the channel access. In the competition part, DS system with common spreading code is used and in the data, hybrid DS/FH system is used. We consider the linear correlation receiver and the hard-limiting correlation receiver as the receiver model. BPSK modulation is also employed. Because hybrid DS/FH systems are not sensitive to variation of the interference power, as we choose a proper chip number N and a frequency hopping number q, we can obtain a steady system performance even though the variation of interference power is severe fading channels such as Rayleigh fading.
Performance analysis of an MC-CDMA system by using an adaptive beamforming technique
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1471~1479
This paper presents an adaptive beamforming algorithm for an MC-CDMA system with an adaptive array antenna. By employing an antenna array at the receiver of an MC-CDMA system, the performance of an MC-CDMA system, which is known to be effective for high data rate transmission due to its robustness to multipath fading and its simplicity for using a simple one-tap equalizer, is shown to be significantly improved. The proposed algorithm for adaptive beanforming in an MC-CDMA system is derived by (1) calculating the error signals between the pilot symbols of desired user and the received pilot signals in frequency domain, (2) transforming the frequency-domain error signals into time-domain error signals, (3) updating the filter coefficients of the adaptive beamformer in the direction of minimizing the MSE. Convergence behavior and performance improvement of the proposed approach are demonstrated through computer simulation by applying it to the conventional MC-CDMA system
Soft-Output Equalization Techniques for DCS 1800 Mobile communication System
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1480~1493
M/B-MC/CDMA performance analysis for high speed data transmission in IS-95 evolution
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1494~1500
In order to provide high speed multimedia data rate service, Multi-Code CDMA has been proposed which converts high speed serial data stream into N parallel low speed data streams with orthogonal PN codes for spreading. However this signal has multi level and causes interferences to be increased at the neighboring cell boundary in the reverse link. Therefore in order to solve the above mentioned problem, M/B-MC/CDMA, in which multi level signal is converted to binary level signal using M/B conversion, is proposed and the performance is compared with MC-CDMA.
Adaptive Logical Link Control for Wireless Internet Service in ITS
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1501~1506
DSRC(Dedicated Short Range Communications), which is a radio mobile communication protocol in ITS, is suited for traffic related information services. But in WAC(Wide-Area wireless communications), we could consider a conventional communication infrastructure in the case of supporting other applications besides ITS. Especially considering the current the trends to introduce wireless internet service into the mobile communication network, wireless internet service in ITS system is valuable. Although ITS LLC(Logical Link Control) protocols recommended by Europe and Japan are effective for traffic related services, it is not suitable for services related with geographical information, image or internet. That is because the data traffic characteristics is changed according to service types. Therefore we suggest a logical link control algorithm effective for traffic information related services as well as internet web service, and analyze its performance. As a result of numerical analysis and simulation, proposed algorithm shows larger performance improvements. For traffic information related services, the performance of DSRC LLC recommended by Europe and Japan is the same as that of proposed LLC protocol. However, for wireless internet web service, the performance of proposed protocol is much better than that of LLC protocol used in Europe and Japan.
Automatic Compensation for Cartesian Feedback Transmitter Imperfections Using the Binary Search Algorithm
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1507~1516
Design of QoS-based Routing Algorithm for Internet Services on Large Scale ATM Networks
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1517~1531
The Internet is recently evolving into the directions which is capable of incorporating stream-type services such as voice and video services. However, the existing Internet can only support a best-effort delivery model and thus it is difficult to satisfy these requirements as well as to provide the QoS beyond a certain degree. Accordingly, it is imperative to develop QoS based routing algorithm in order to allow the routing by the user's QoS demand and to be applied into wide area networks. In this thesis, we presented new routing algorithms and made performance evaluations. The proposed algorithms allow the routing by the user’s QoS demand level in order to provide the diverse Internet application services based on ATM network environment that is expected to play a role as an infrastructure of high-speed communication network. They also have a feature of shortening the waiting time for address analysis and have a quality-proven characteristics with enhanced network scalability.
Adaptive Error Control Based on Traffic Type and Channel Error Rate in Wireless ATM
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1532~1538
In general, because error rate of wireless link is higher than that of wired link, DLC layer protocol for wired network with low error rate is not proper for wireless environments. In addition, the conventional DLC layer protocol for wireless network is optimized for the low-speed data service, so it is difficult to use conventional DLC protocol in the current mobile communication environments handing high-speed and multimedia services. Therefore, a DLC layer protocol that is suitable to current wireless communication environments is required. In this paper, we propose a novel error control scheme that supports a variety of traffic attribute and is applicable to high-speed and multimedia data service in WATM. The proposed scheme provides enhanced throughput performance for real-time traffic by using modified ASR ARQ without ACK and reduces loss rate by using FEC in the case of high error condition. Also, for non real-time traffic, the use of ASR ARQ without ACK enhances throughput performance and delay time is decreased by using FEC in the case of high error rate channel. As a result of simulation, the proposed scheme has better performance than conventional ASR ARQ protocol in view of delay and throughput.
A Study on Chaotic Secure Communication of Chua's Circuit with Lossy Transmission Line
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1539~1545
In this paper, a transmitter and a receiver using two identical Chua's circuits are proposed and a wire secure communications are investigated. A secure communication method in which the desired information signal is synthesized with the chaos signal created by the Chua's circuit is proposed and information signal is demodulated also using the Chua's circuit. The proposed method is synthesizing the desired information with the chaos circuit by adding the information signal to the chaos signal in the wire transmission system. After transmitting the synthesized signal through the wire transmission system, it is confirmed the feasibility of the secure communication from result of demodulated signals recovered wire tapped signals.
A Study on Reliability Evaluation Using Dynamic Fault Tree Algorithm
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1546~1554
In this paper, Dynamic Fault Tree algorithm(DFT algorithm) is presented. This algorithm provides a concise representation of dynamic fault tolerance system including fault recovery techniques with fault detection, mask and switching function. And this algorithm define FDEP, CSP, SEQ, PAG gate which captures the dynamic characteristics of system. It show that this algorithm solved the constraints to satisfy the dynamic characteristics of system which there are in Markov and also this is able to satisfy the dynamic characteristics of system which there are in Markov and also this is able to covered the disadvantage of Fault tree methods. To show the key advantage of this algorithm, a traditional method, that is, Markov and Fault Tree, applies to TMR and Dual-Duplex systems with the dynamic characteristic and a presented method applies to those. He results proved that the DFT algorithm for solving the problems of the system is more effective than the Markov and Fault tree analysis model..
Efficient Prediction-based Video Rate Control Technique
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1555~1562
Various video rate control techniques have been proposed for the transmission of video under fixed channel capacity. In most techniques, the coding parameters and quantizer scaling factors are determined based on information derived from previously coded data. In this paper, an successfully used for video rate-control. Experimental results show that the proposed prediction-based rate control scheme can efficiently regulate the bit-rate caused by dramatic scene change and have better PSNR performance than the TM5 rate control mechanism.
Performance Analysis on Soft Decision Decoding using Erasure Technique
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1563~1570
This paper relates to the soft decision method with erasure technique in digital terrestrial television broadcasting system. The proposed decoder use the CSI derived from using the pilots in receiver. The active real(I) and imaginary(Q) data are transferred to the branch metric calculation block that decides the Euclidean distance for the soft decision decoding and also the estimated CSI values are transferred to the same block. After calculating the Euclidean distance for the soft decision decoding, the Euclidean distance of branch metric is multiplied by CSI. To do so, new branch metric values that consider each carrier state information are obtained. We simulated this method in better performance of about 0.15dB to 0.17dB and 2.2dB to 2.9dB in Rayleigh channel than that of the conventional soft decision Viterbi decoding with or without bit interleaver where the constellation is QPSK, 16-QAM and 64-QAM.
Design and Implementation of Modulator Channel Card and VLSI Chip for a Wideband CDMA Wireless Local Loop System
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1571~1578
In this paper, we present the Modulator Channel Card and VLSI chip for the Radio Transceiver Unit (RTU) of direct sequence code division multiple access (DS-CDMA) Wireless Local Loop (WLL) System. The Modulator Channel Card is designed and implemented using ASIC's, FPGA's and DSP's. The ASIC, compliance with Common Air Interface specification proposed by ETRI, has 40K gates which is designed to operate at 32MHz, and is fabricated using
CMOS process. The ASIC carries out for I- or Q- phase data channel signal processing at a time, where each data channel processing consists of channel coding, block interleaving, scrambling, Walsh modulation, Pseudo-Noise (PN) spreading, and baseband filtering. The Modulator Channel Card has been integrated as a part of RTU of WLL system and is confirmed that it meets all functional and performance requirements.
A Scalable Bias-dependent P-HEMT Noise Model with Single Drain Current Noise Source
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1579~1587
Bias-dependent noise models of
gate length P-HEMT's which are scalable with gate width are proposed. To predict S-parameters of the P-HEMT's the intrinsic parameters except for
subtracted the offsets introduced in this paper are normalized to the gate width and then scaled. The small-signal model parameters are expressed as fitting functions of the drain current to
ratio and gate width. In addition, to estimate accurately noise parameters the noise temperature
of the intrinsic resistance, the equivalent noise conductance
of the gate current noise source, and the equivalent noise conductance
of the drain current noise source are adopted as the noise model parameters. The extracted values of
are nearly independent of drain current and gate width and their average is around the ambient temperature. The extracted values of
are small enough to be neglected to the circuit characteristics. From the comparison of the noise model with only
and that having
to the measured data it is fund that even the former model is in good agreement with the measured noise parameters. Thus, from a practical point of view the noise model having only the drain current noise source is confirmed as a scalable bias-dependent model.
A Signaling Processor IC for Land Mobile Radio System
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1588~1596
This paper describes a signaling processor IC for land mobile radio systems. This IC generates CTSS tone or DCS code signals for signaling between the land mobile radio systems and decodes them to open the audio path. The CTSS tone or DCS code signals occupy the subaudio band and are transmitted with voice signal. The audio and subaudio paths consist of switched capacitor filters. The IC has been implemented in 0.6-
2-poly 3-metal CMOS process. The chip size is 3 mm
4.3 mm and total current is about 3.4 ㎃ at 3.3 V.
Design of 234.7 MHz Mixed Mode Frequency Multiplication & Distribution ASIC for ATM Switching System
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1597~1602
An analog / digital mixed mode frequency multiplication and distribution ASIC for switch link or network synchronization of ATM switching system for B-ISDN has designed. This ASIC generates 234-7 MHz system clock and 77.76 MHz, 19.44 MHz user clocks using 46.94 MHz external clock. It also includes digital circuits for checking and selecting between the two external clocks. For effective ASIC design, full custom technique is used in analog PLL circuit and standard cell based technique is used in digital circuit. Resistors and capacitors are specially designed so the chip can be implemented in 0.8
digital CMOS technology.
Effective mask design for the improvement of latch-up characteristics in CMOS
The Journal of Korean Institute of Communications and Information Sciences, volume 24, issue 10A, 1999, Pages 1603~1610